Polarized relay



W. H. HOPPE POLARIZED RELAY July 18, 1933.

Filed Oct. 16. 1950 mm m ATTORNEY Patented July 18, 1933 lUNl-TED STATESPATENT OFFICE WALTER H. norm, or nocnnsrna, new YORK, essienon TOGENERAL RAILWAY SIGNAL COMPANY, OF ROCHESTER, NEW YORK POLARIZED RELAYApplication filed October 16, 1930. Serial No. 439,091.

This invention relates to polarized relays and more particularly to thepolarized type ofrelays used in a centralized traffic controlling systemfor railroads or which are often referred to as telephone relays.

The usual type of polarized three position telephone relays employs twooperating electro-magnets so arranged as to attract an armature to oneor the other according to the direction of current flowing in theelectromagnet coils. This is accomplished by arranging theelectro-magnets so that the flux emanating from their cores is relatedto a flux from a permanent magnet in a way to unbalance the fiuX passageon one side or the other'of the armature axis according to the currentflow,'thereby causing a corresponding motion of the armature; The use ofsuch a relay in a, centralized traflic controlling system on a railroadnecessitates that its size be kept as small as possible because of thelarge number required and the comparatively small space in which it isnecessary for I them ,to'be grouped. The usual type of polarized relaycan not bev conveniently grouped in such a system because of the largedimensions made necessary by its two electro-magnetsand consequently isnot particularly adapted to such a system. A

In View of these facts, it is proposed in accordance" with thisinventionto provide a small dimension polarized relay made possible by the useofonly one electro-magnet which will be simple and dependable in itsoperation. 1

Other objects, purposes and characteristic features of the inventionwill appear as the description thereof progresses, during whichreferences will bemade to the accompanying drawing which shows theinvention in a wholly diagrammatic Way to make it easily understood,rather than to illustrate the particular construction preferablyemployed in practice, and in which Fig; 1 shows a top viewof theinvention.

Fig.2 shows a side view of the invention. Fig 3 is 'a perspective anddiagrammatic View of the invention with the armature shown away from itsnormal position to facilitate tracing the various paths of flux.

The relay as shown 011 the accompanying drawing includes a soft ironcore 1 with a threaded mounting extension 1 upon Which a carrier member2 is fastened by nut 3. The core 1 carries a coil 4 which is to beenergized by a changing polarity of direct current to thereby form anelectro-magnet. Equally spaced from core 1 on the carrier member 2 aremounted permanent magnets 5 and 6 by clamps 7 and S-to thus extendparallel to core 1 and wit-h their free ends of opposite polarity. Alsomounted on the extension 1 of core 1 is a U-shaped strip 9 also fastenedat its center point. by nut 3 and and with its ends extending parallelto and equally spaced from the core 1 but interspaced in quadraticrelation to the permanent magnets 5 and 6. 1

The movable members of the relay comprise an armature 10 pivotedcentrally with I respect to core 1 with its axis 11 in line with theends of the U-shaped member 9 and suitably supported by means not shownon the drawing. This permits a motion thereabout either againstpermanent magnet 5 or permanent magnet 6, and thereturn of armature 10is assured by means of a biasing spring 12 acting upon an armature arm10 The circuit changing means consistof insulated contact arms 13 and14: adapted to engage either stationary contact 15 or 16 respectively,all of which is shown diagrammatically to simplify the drawing.

The path of the flux from the permanent magnets 5 and 6 when the coil 4is deenergized can be considered to flow as follows :the flux producedby permanent magnet 5 flows out of its north pole N, through an air gapto armature 10, through armature 10, through an air gap to the southpole S of permanent magnet 6. where it is strengthened bythe fluxproducedby it and flows out its opposite end, through the carrier member2 back to the opposite end of permanent magnet 5. This path is'of lowerreluctance than any other path because the flux values of the permanentmagnets are additive, and the magnetic force produced acts onthearmature 10 in such a way that it is equally distributed on each side ofits axis 11 thereby producing no turning effort and the armature 10remains in its mechanicallybiased neutral position.

The flux in the center core 1 and the legs of the U-shaped member 9under the above deenergized condition will be the resultant value of themagnetic forces of the two permanent magnets. Considering that thestrength of the two permanent magnets is substantially equal, and thatthe structure is symmetrical, the flux in the center coreand the leakagestrips is of a negligible value, because the flux tending to flow inthese parts from the north. pole N of permanent magnet 5 is equallyopposed by the flux tending to flow in these parts from the north poleof permanent magnet 6.

. If now it isvconsidered that the coil 4 is energized with a certaindirection of current so that the free end of the core 1 is made a northpole, the flux emanating therefrom finds a path of higher permeancethrough the right hand half of the armature 10 to'the permanent magnet 6because the direction is such that it is additive to the permanentmagnet flux in this half but is bucking the permanent magnet flux in theleft hand half. This causes a greater amount of flux to flow in theright hand half which unbalances the mag netic force about the axis 11and the armature 10 is rotated against the permanent magnet 6 whichengages contact arm 13 with stationary contact 15'. I l

A current applied to the coil 4 in a direction opposite to the directionjust assumed makes the free end of the core 1 a south pole and it isobvious that the armature willbe attracted to permanent magnet 5 due toa similar unbalancing of magnetic forces about the axis 11, whichresults in'contact arm 14 engaging stationary contactlfi.

The purpose of the 'U-shaped member 9 is to provide a path for thepermanent magnet flux which is opposed by the flux from core 1 producedduring the energization of coil 4,

thus obviating the tendency for the opposed permanent magnet to becomedemagnetized. For example, when the core 1 is made a north pole at itsfree end, the flux emanating therefrom opposesthenormal flux flowingfrom permanent magnet 5 in the left hand half of armature 10, but theflux inpermanent magnet 5 isnot greatly reduced because it finds anauxiliary return'path through the legs of the U-s'haped member 9 toitssouth pole. It

should be noted that the legs of the U-shaped member 9 will likewisecarry the leakage flux of the permanent magnet 6 when the energy on coil4 is reversed, bat ina reverse direction to the previously assumed-case.

It is found in practice that two straight bar permanent magnets can bemanufactured with very slight variations in magnetic strength orreluctance, but if such variation is discovered, itseffeot on themagnetic circuit can be compensated for by adjusting the permanentmagnets in their retaining clamps 7 and 8. It is possible to employ asingle U-shap-ed permanent magnet in the place of the two bar magnets,but it is found difficult to evenly magnetize such a magnet throughoutits length. Such uneven magnetism, with the core 1 evenly spaced between5 and 6, causes a, circulating path of flux from the stronger portionthrough the center core 1 and also the legs of the U-shaped member 9 andthe corresponding half of the armature 10, which imbalances the magneticforce on the armature as well as unbalacing the required operatingenergy.

Having shown and described one embodiment of the present invention, itis desired to be understood that this form is selected to facilitate inthe disclosure thereof rather than to limit the number of forms which itmay assume; and, it is to'be further understood that variousmodifications and alterations maybe applied to the form shown to meetthe requirements of practice, without in any manner departing from thespirit or scope of the present invention, or the idea of means underlyinthe same.

Having thus described my invention, what I claim is:

1. A polarized relay comprising a carrier member of magnetic material,an electromagnet including a soft iron core with one end rigidlyvfastened to said carrier'member, two straight permanent magnets withrespectively alternate poles fastened to said carrier member and locatedin a common plane with said electro-magnet equally spaced therefrom, twostrips of magnetic material with one end of each fastened to saidcarrier member and extending parallel to said electr c-magnet, equallyspaced therefrom, and located in a plane which is substantially at rightangles to the aforesaid common plane of the permanent magnets, anarmature with its axis located in said plane of the magnetic strips andelectromagnet and adapted to move there-about into contact with eitherof the free ends of said permanent magnets, said armature being biasedto a neutral position, and havin suitable circuit changing means attachethereto. i

2. A polarized relay comprising a carrier member of magnetic material,an electromagnet including a soft iron core with one end rigidlyfastened to said carrier member, two permanent magnets with oppositepoles adjustably clamped to said carrier member equidistant from andparallel to said electromagnet core, a U-shaped member fastened at itsmid point to said carrier member at the point of connection with saidelectromagnet core and its sides extending parallel thereto equallyspaced therefrom and substantially at right angles to said permanentmagnets, an armature with an axis Sllibfififilh tially at right anglesto the plane of said permanent magnets and movable to make contact witheither of the free ends thereof, and means acting on said armature tobias it to its neutral position.

3. A polarized relay comprising a carrier member holding two permanentmagnets with opposite poles adjustably clamped thereto and extending inspaced parallel relationship substantially at right angles to saidcarrier member thereby forming a U- shaped assembly, an integral membershaped similarly to said U-shaped assembly, an electro-magnet with anextending soft iron core, the extending portion of said electro-magnetcore passing through the central part of said U-shaped assembly and thecentral part of said U-shaped integral member, a nut threaded on theextending portion of said electromagnet core thereby clamping the twoaforesaid U-shaped members to the core in a fixed quadrature relation toeach other, and an armature pivoted. and biased in central relationshipto the free end of said electro-magnet core and arranged to operatecontacts by its movement against either of the two permanent magnets inaccordance with the polarity of the electro-magnet energization.

4. A relay including two permanent magnets, an electro-magnet, a carriermember for said permanent magnets and said electromagnet, two elongatedstrips of magnetic material fastened to said carrier member parallel toand symmetrically disposed relatively to said permanent magnets, and anarmature biased to a neutral position and adapted to move toward eitherof said permanent magnets according to the polarity of saidelectro-magnet energization.

5. A polarized relay comprising an electromagnet with a soft iron corehaving a threaded mounting extension, a carrier member of magneticmaterial fastened at its central point to the threaded extension of saidcore adjacent said electro-magnet, two elongated permanent magnetsadjustably clamped to said carrier member at their extreme oppositepoles and extending in equally spaced and parallel relationship to saidelectro-magnet, a movable member biased to a neutral position andadapted to move against either of said permanent magnets according tothe polarity of the electro-magnet energization,

and a leakage flux path partially encircling said electro-magnet whichincludes two mag netic strips interspaced in quadrature parallelrelation to said permanent magnet.

WALTER H. HOPPE.

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